How do you remove mildew stains from vinyl with a canvas backing?
Mildew is a fungus that thrives in damp places. The first step in removing it is to dry the item in a warm, dry spot. Brush off as much of the mildew as possible, then use a cleanser with an acidic, antifungal component. A mixture of salt, vinegar, and water (up to full-strength vinegar, depending on the amount of mildew) will work on most fabrics. On white fabrics, rub with a mixture of lemon juice and salt, then place the item in the sun. If your vinyl item has sat for a long time with mildew on it, you may be out of luck. You also can use the following mildew remover: 1 tablespoon powdered laundry detergent combined with 1 quart chlorine bleach and 22 quarts water. Always wear protective gloves when using this cleaner.